TW201412919A - Adhesive - Google Patents

Abstract

Provided is an adhesive containing a polyurethane resin, the adhesive having excellent initial reworkability together with adhesion reliability over time when adhered to an adherend. Also provided are a surface protective film and an adhesive sheet having an adhesive layer made of such an adhesive. Further provided are optical components and electronic components to which such an adhesive sheet or surface protective film is adhered. This adhesive contains a polyurethane resin wherein, taking the initial adhesive force immediately after adhesion to an acrylic board as (A) and taking the adhesive force after one day at 70 DEG C after adhesion to the acrylic board as (B), the initial adhesive force (A) is from 0.001 N/20 mm to 2.0 N/20 mm and the adhesive force (B) after one day at 70 DEG C is 2.0 times or more the initial adhesive force (A).

Description

Adhesive

This invention relates to an adhesive. When the adhesive of the present invention is attached to the adherend, it is excellent in initial reworkability, and is excellent in reliability after passage of time. Further, the present invention relates to an adhesive sheet having an adhesive layer containing such an adhesive on at least one side of a substrate layer. Further, the present invention relates to a surface protective film having an adhesive layer containing such an adhesive on one side of a substrate layer. The adhesive sheet of the present invention can be preferably used, for example, for the purpose of adhering and fixing various members such as an optical member or an electronic member to each other. The surface protective film of the present invention can be preferably used, for example, for attachment to a surface of an optical member or an electronic member to protect the surface, and the like.

In order to prevent processing, assembly, inspection, and the like, an optical member such as an LCD (Liquid Crystal Display), an organic EL (Electroluminescence), a touch panel using the same, a lens portion of a camera, an electronic device, or the like In the case of damage to the surface during transportation, a surface protective film is usually attached to the exposed side. Such a surface protective film is peeled off from an optical member or an electronic member at the time when surface protection is not required.

In the case where the surface protective film is attached by hand work, air bubbles are sometimes caught between the adherend and the surface protective film. Therefore, there have been reported a number of techniques for improving the wettability of the surface protective film so as not to entrap air bubbles when attached. For example, a surface protective film made of a polyxanthene resin having a faster wetting speed is used for the adhesive layer. However, when a polyoxyxylene resin is used for the adhesive layer, the adhesive component is likely to contaminate the adherend and is used for protection. There is a problem in protecting a surface protective film on the surface of a member having low contamination, such as an optical member or an electronic member.

As the surface protective film which is less contaminated by the adhesive component, a surface protective film obtained by using an acrylic resin for the adhesive layer is known. However, the surface protective film obtained by using an acrylic resin for the adhesive layer is inferior in wettability, so when the surface protective film is attached by hand work, it is sometimes rolled between the adherend and the surface protective film. Into the bubble. In the case where the acrylic resin is used for the adhesive layer, there is a problem in that peeling is likely to occur at the time of peeling, and it is used as a surface protective film for protecting the surface of a member such as an optical member or an electronic member, which is particularly resistant to foreign matter. There is a problem.

As a surface protective film which can simultaneously achieve excellent wettability, low contamination, and reduced stickiness, a surface protective film obtained by using a polyurethane resin for an adhesive layer has recently been reported (for example, refer to Patent Document 1) ).

Here, depending on the application, when the surface protective film is attached to the adherend by a manual operation, excellent wettability is required and excellent initial reworkability is required. The surface protective film attached to the adherend may be peeled off immediately after attaching in order to correct the positional deviation or the like. In this case, it is required to be peeled off gently without deformation, and thereafter it is good. Attach it without wrapping it into the bubble. Further, in the application in which the re-peeling is performed infrequently after the re-attachment as described above, in order to avoid the problem of easy dropping, it is necessary to have excellent adhesion reliability after the passage of time.

In view of the above, there is a need for an adhesive comprising a polyurethane-based resin which is excellent in initial reworkability when adhered to an adherend and which is excellent in reliability after passage of time. In addition, it is effective to provide an adhesive sheet using such an adhesive, for example, in which the various members such as an optical member or an electronic member are adhered to each other. Further, when a surface protective film using such an adhesive can be provided, it is effective for, for example, application to a surface of an optical member or an electronic member to protect the surface.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2006-182795

An object of the present invention is to provide an adhesive comprising a polyurethane resin which is excellent in initial reworkability when attached to an adherend and which is excellent in reliability after passage of time. Further, an object of the present invention is to provide an adhesive sheet or a surface protective film which has an adhesive layer containing such an adhesive. Further, an object of the present invention is to provide an optical member or an electronic member to which such an adhesive sheet or a surface protective film is attached.

The adhesive of the present invention comprises a polyurethane resin, and the initial adhesive force immediately after attaching to the acrylic plate is A, attached to an acrylic plate and passed at 70 ° C. When the adhesive force is set to B after 1 day, the initial adhesive force A is 0.001 N/20 mm to 2.0 N/20 mm, and the adhesive force B after one day at 70 ° C is 2.0 times or more of the initial adhesive force A. .

In a preferred embodiment, the polyurethane resin is a polyamine group obtained by curing a composition containing a polyol (A) having two or more OH groups and a polyfunctional isocyanate compound (B). Formate resin.

In a preferred embodiment, the polyol (A) is two or more kinds of polyols.

In a preferred embodiment, at least one of the above two or more kinds of polyols is a polyol having two OH groups, and at least one of them is a polyol having three or more OH groups.

In a preferred embodiment, the number average molecular weight Mn of the polyol having two OH groups is 6000 or more, and the number average molecular weight Mn of the polyol having three or more OH groups is 2,000 or more.

In a preferred embodiment, the number average molecular weight Mn of the polyol having two OH groups is less than 6,000, and the number average molecular weight Mn of the polyol having three or more OH groups is less than 2,000, and the above polyol ( A) The equivalent ratio of the NCO group to the OH group in the above polyfunctional isocyanate compound (B) is less than 1.3 based on the NCO group/OH group.

In a preferred embodiment, the polyol (A) contains 50% by weight or more of a polyol having two OH groups.

In a preferred embodiment, the amount of the catalyst (C) used to obtain the polyurethane resin by curing is 0.01 parts by weight or more based on 100 parts by weight of the polyol (A).

The adhesive sheet of the present invention has an adhesive layer containing the adhesive of the present invention on at least one side of the substrate layer.

The optical member of the present invention is attached to the adhesive sheet of the present invention.

The electronic component of the present invention is attached to the adhesive sheet of the present invention.

The surface protective film of the present invention has an adhesive layer containing the adhesive of the present invention on one side of the substrate layer.

In a preferred embodiment, the surface protective film of the present invention is used for surface protection of optical members or electronic members.

The optical member of the present invention is attached to the surface protective film of the present invention.

The electronic component of the present invention is attached to the surface protective film of the present invention.

According to the present invention, it is possible to provide an adhesive comprising a polyurethane-based resin which is excellent in initial reworkability when attached to an adherend and which is excellent in reliability after passage of time. Further, an adhesive sheet or surface protective film having an adhesive layer containing such an adhesive can be provided. Further, an optical member or an electronic member to which such an adhesive sheet or a surface protective film is attached can be provided.

1‧‧‧ substrate layer

2‧‧‧Adhesive layer

10‧‧‧Adhesive sheet or surface protective film

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing a surface protective film according to a preferred embodiment of the present invention.

"A. Adhesive"

The adhesive of the present invention contains a polyurethane resin as a main component. The content of the polyurethane resin in the adhesive of the present invention is preferably from 90% by weight to 100% by weight, more preferably from 95% by weight to 100% by weight, still more preferably from 98% by weight to 100% by weight. %. The adhesive may be used alone or in combination of two or more.

When the initial adhesive force of the adhesive of the present invention is set to A immediately after being attached to the acrylic plate, the initial adhesive force A is 0.001 N/20 mm to 2.0 N/20 mm, preferably 0.005 N/20 mm to 1.8. N/20 mm, further preferably 0.01 N/20 mm to 1.5 N/20 mm, particularly preferably 0.1 N/20 mm to 1.3 N/20 mm, most preferably 0.15 N/20 mm to 1.0 N/20 mm. When the initial adhesive force A is within the above range, the adhesive of the present invention is excellent in initial reworkability when attached to the adherend. Further, the measurement of the initial adhesion A described above will be described below.

When the adhesive of the present invention is applied to an acrylic plate and the adhesive force after one day at 70 ° C is set to B, the adhesive force B after one day at 70 ° C is preferably 0.1 N / 20 mm or more, more preferably 0.5 N/20 mm or more, further preferably 1.0 N/20 mm or more, and particularly preferably 1.5 N/20 mm or more. The above upper limit of the adhesive force B after one day at 70 ° C is preferably 10 N/20 mm or less. When the adhesive force B after the lapse of one day at 70 ° C is within the above range, the adhesive of the present invention is excellent in reliability after being attached to the adherend. Further, the measurement of the adhesive force B after the above one day at 70 ° C will be described below.

The adhesive force B of the adhesive of the present invention after the lapse of one day at 70 ° C is 2.0 times or more, preferably 3.0 times or more, more preferably 4.0 times or more, and even more preferably 5.0 times or more of the initial adhesive force A. The best is 10 times or more. The upper limit of the magnification of the adhesive force B with respect to the initial adhesive force A after one day at 70 ° C is preferably 100 times or less. By using The ratio of the adhesion B to the initial adhesive force A after one day at 70 ° C is within the above range, and the adhesive of the present invention is excellent in reliability after being attached to the adherend. . Further, the measurement of the adhesive force B after the above one day at 70 ° C will be described below.

The polyurethane resin is preferably obtained by curing a composition containing a polyol (A) having two or more OH groups and a polyfunctional isocyanate compound (B). By using such a polyurethane-based resin, the adhesive of the present invention is excellent in initial reworkability when attached to an adherend, and is excellent in reliability after passage of time. Further, by using such a polyurethane resin, the adhesive of the present invention can simultaneously achieve excellent wettability, low contamination, and reduced stickiness.

The polyol (A) may be used alone or in combination of two or more. It is preferred that the polyol (A) is two or more kinds of polyols. When the polyol (A) is a mixture of two or more kinds of polyols, the adhesive of the present invention is excellent in initial reworkability when attached to an adherend, and is excellent in reliability after passage of time. Further, since the polyol (A) is two or more kinds of polyols, the adhesive of the present invention can simultaneously achieve excellent wettability, low pollution, and reduced stickiness.

The polyol (A) is preferably two or more kinds of polyols. In this case, it is preferred that at least one of the two or more polyols is a polyol having two OH groups, and at least one of them has More than three OH group polyols. By using such a polyol (A), the adhesive of the present invention is excellent in initial reworkability when attached to an adherend, and is excellent in reliability after passage of time. Further, by using such a polyol (A), the adhesive of the present invention can simultaneously achieve excellent wettability, low contamination, and reduced stickiness.

The number average molecular weight Mn of the polyol having two OH groups which may be contained in the polyol (A) is preferably 6,000 or more, more preferably 7,000 or more, still more preferably 8,000 or more, and still more preferably 9000 or more. The upper limit of the number average molecular weight Mn is preferably 20,000 or less. By adjusting the number average molecular weight Mn of the polyol having two OH groups which may be contained in the polyol (A) to the above range, the adhesive of the present invention is initially attached to the adherend. The reworkability is excellent, and the reliability is excellent after the passage of time. Further, by adjusting the number average molecular weight Mn of the polyol having two OH groups which can be contained in the polyol (A) to the above range, the adhesive of the present invention can simultaneously achieve excellent wettability and low pollution, Reduced stains.

The number average molecular weight Mn of the polyol having three or more OH groups which may be contained in the polyol (A) is preferably 2,000 or more, more preferably 2,500 or more, further preferably 3,000 or more, and particularly preferably 3,500 or more. . The upper limit of the number average molecular weight Mn is preferably 20,000 or less. By adjusting the number average molecular weight Mn of the polyol having three or more OH groups which may be contained in the polyol (A) to the above range, the adhesive of the present invention is initially processed after being attached to the adherend. It is excellent in the properties and is excellent in reliability after the passage of time. Further, by adjusting the number average molecular weight Mn of the polyol having three or more OH groups which can be contained in the polyol (A) to the above range, the adhesive of the present invention can simultaneously achieve excellent wettability and low pollution. Sex and paste reduction.

The polyol (A) preferably contains 50% by weight or more of a polyol having two OH groups, more preferably 55% by weight or more, still more preferably 60% by weight or more, and still more preferably 62% by weight. The above is particularly preferably 65 wt% or more, and most preferably 67 wt% or more. By using such a polyol (A), the adhesive of the present invention is excellent in initial reworkability when attached to an adherend, and is excellent in reliability after passage of time. Further, by using such a polyol (A), the adhesive of the present invention can simultaneously achieve excellent wettability, low contamination, and reduced stickiness.

Examples of the polyol (A) include polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil polyols.

The polyester polyol can be obtained, for example, by an esterification reaction of a polyol component and an acid component.

Examples of the polyol component include ethylene glycol, diethylene glycol, 1,3-butylene glycol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentane. Alcohol, 2-butyl-2-ethyl-1,3- Propylene glycol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-nonanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, polypropylene glycol, and the like.

Examples of the acid component include succinic acid, methyl succinic acid, adipic acid, pimelic acid, sebacic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-fourteen. Alkanoic acid, dimer acid, 2-methyl-1,4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, Phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalene dicarboxylic acid, 4,4'-biphenyldicarboxylic acid, such acid anhydrides, and the like.

Examples of the polyether polyol include water, low molecular weight polyol (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), and dihydroxy groups. a benzene (catechol, resorcin, hydroquinone, etc.) or the like as an initiator, and an addition polymerization of an alkylene oxide such as ethylene oxide, propylene oxide or butylene oxide Ether polyol. Specific examples thereof include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

Examples of the polycaprolactone polyol include a caprolactone-based polyester diol obtained by ring-opening polymerization of a cyclic ester monomer such as ε-caprolactone or σ-valerolactone.

Examples of the polycarbonate polyol include a polycarbonate polyol obtained by subjecting the above polyol component to carbon trichloride to undergo polycondensation reaction; and the above polyol component and dimethyl carbonate, diethyl carbonate, and carbonic acid A transesterification condensation of a carbonic acid diester such as propyl ester, diisopropyl carbonate, dibutyl carbonate, ethyl butyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate or dibenzyl carbonate. a polycarbonate polyol; a copolymerized polycarbonate polyol obtained by using two or more kinds of the above polyol components; and a polycarbonate polyol obtained by esterifying the above various polycarbonate polyols with a carboxyl group-containing compound An alcohol; a polycarbonate polyol obtained by subjecting the above various polycarbonate polyols to a hydroxyl group-containing compound to etherification reaction; a polycarbonate polyol obtained by transesterification of the above various polycarbonate polyols with an ester compound Alcohol; the above various polycarbonate polyols and hydroxyl groups a polycarbonate polyol obtained by subjecting a compound to a transesterification reaction; a polyester-based polycarbonate polyol obtained by subjecting the above various polycarbonate polyols to a polycondensation reaction to a polycondensation reaction; A copolymerized polyether-based polycarbonate polyol obtained by copolymerizing an alcohol and an alkylene oxide.

The castor oil-based polyol is, for example, a castor oil-based polyol obtained by reacting a castor oil fatty acid with the above-described polyol component. Specifically, for example, a castor oil-based polyol obtained by reacting a castor oil fatty acid with polypropylene glycol can be mentioned.

The polyfunctional isocyanate compound (B) may be used alone or in combination of two or more.

As the polyfunctional isocyanate compound (B), any appropriate polyfunctional isocyanate compound which can be used in the urethanization reaction can be used. Examples of such a polyfunctional isocyanate compound (B) include a polyfunctional aliphatic isocyanate compound, a polyfunctional alicyclic isocyanate, and a polyfunctional aromatic isocyanate compound.

Examples of the polyfunctional aliphatic isocyanate compound include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, and 1,2-propyl propyl diisocyanate. 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and the like.

Examples of the polyfunctional alicyclic isocyanate compound include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, and isophorone diisocyanate. And hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated toluene diisocyanate, hydrogenated tetramethyl xylene diisocyanate, and the like.

Examples of the polyfunctional aromatic diisocyanate compound include phenyl diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, and 4,4'. -diphenylmethane isocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, xylene Isocyanate, etc.

Examples of the polyfunctional isocyanate compound (B) include various types as described above. A trimethylolpropane adduct of a functional isocyanate compound, a biuret obtained by reacting with water, a terpolymer having an isocyanurate ring, or the like. Moreover, these may be used in combination.

The polyfunctional isocyanate compound (B) is preferably a polyfunctional aromatic diisocyanate compound. By using a polyfunctional aromatic diisocyanate compound as the polyfunctional isocyanate compound (B), whitening of the obtained adhesive can be suppressed, and high transparency can be imparted. If the adhesive of the present invention can be imparted with high transparency, the surface protective film of the present invention having the adhesive layer containing the adhesive of the present invention can be improved in transparency, and can be on the surface of the optical member or the electronic member. The inspection is performed accurately with the surface protective film attached thereto.

The polyurethane resin is preferably obtained by curing a composition containing the polyol (A) and the polyfunctional isocyanate compound (B). In such a composition, any suitable other components other than the polyol (A) and the polyfunctional isocyanate compound (B) may be contained within the range not impairing the effects of the present invention. Examples of such other components include a resin component other than a catalyst or a polyurethane resin, a tackifier, an inorganic filler, an organic filler, a metal powder, a pigment, a foil, and a softener. , plasticizers, anti-aging agents, conductive agents, UV absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, etc.

With respect to the weight ratio of the polyol (A) to the polyfunctional isocyanate compound (B), the polyfunctional isocyanate compound (B) is preferably 30 parts by weight or less, more preferably 28 parts by weight, based on 100 parts by weight of the polyol (A). Hereinafter, it is more preferably 25 parts by weight or less, and particularly preferably 23 parts by weight or less. With respect to the lower limit of the weight ratio of the polyfunctional isocyanate compound (B), the polyfunctional isocyanate compound (B) is preferably 5 parts by weight or more based on 100 parts by weight of the polyol (A). When the weight ratio of the polyol (A) to the polyfunctional isocyanate compound (B) is adjusted to the above range, the adhesive of the present invention is excellent in initial reworkability when attached to the adherend, and after the passage of time It is then excellent in reliability. Further, by adjusting the weight ratio of the polyol (A) to the polyfunctional isocyanate compound (B) to the above range, the present invention The adhesive can achieve excellent wettability, low pollution, and reduced stickiness.

The equivalent ratio of the NCO group to the OH group in the polyol (A) and the polyfunctional isocyanate compound (B) is preferably from 0.1 to 5.0, more preferably from 0.2 to 4.0, still more preferably 0.3, based on the NCO group / OH group. ~3.0. When the equivalent ratio of the NCO group/OH group is adjusted to the above range, the adhesive of the present invention is excellent in initial reworkability when attached to the adherend, and is excellent in reliability after passage of time. Further, by adjusting the equivalent ratio of the NCO group/OH group to the above range, the adhesive of the present invention can simultaneously achieve excellent wettability, low contamination, and reduced stickiness. Further, in the case where a polyol having two OH groups having a number average molecular weight Mn of less than 6,000 and a polyol having three or more OH groups having a number average molecular weight Mn of less than 2,000 are used together as the polyol (A) The equivalent ratio of the NCO group to the OH group is preferably from less than 1.3, more preferably from 0.1 to 1.2, still more preferably from 0.1 to 1.1, still more preferably from 0.1 to 1.0, based on the NCO group/OH group. When a polyol having two OH groups having a number average molecular weight Mn of less than 6,000 and a polyol having three or more OH groups having a number average molecular weight Mn of less than 2,000 are used in combination as the polyol (A), When the equivalent ratio of the NCO group/OH group is adjusted to the above range, the adhesive of the present invention is excellent in initial reworkability when attached to the adherend, and is excellent in reliability after passage of time. Further, when a polyol having two OH groups having a number average molecular weight Mn of less than 6,000 and a polyol having three or more OH groups having a number average molecular weight Mn of less than 2,000 are used in combination as the polyol (A) By adjusting the equivalent ratio of the NCO group/OH group to the above range, the adhesive of the present invention can simultaneously achieve excellent wettability, low contamination, and reduced stickiness.

When the composition containing the polyol (A) and the polyfunctional isocyanate compound (B) is cured to obtain a polyurethane resin, block polymerization can be employed without damaging the effects of the invention. Or any appropriate method such as a urethanation reaction method such as solution polymerization.

In order to harden the composition containing the polyol (A) and the polyfunctional isocyanate compound (B), it is preferred to use a catalyst (C). As such a catalyst (C), for example, an organic metal can be cited. A compound, a tertiary amine compound, or the like.

Examples of the organometallic compound include an iron compound, a tin compound, a titanium compound, a zirconium compound, a lead compound, a cobalt compound, and a zinc compound. Among these, an iron-based compound is preferred in terms of high reactivity.

Examples of the iron-based compound include iron acetylate pyruvate and iron 2-ethylhexanoate.

Examples of the tin-based compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin maleate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, and methanol. Butyltin, tributyltin acetate, triethyltin acetate, tributyltin ethanol, dioctyltin oxide, dioctyltin dilaurate, tributyltin chloride, tributyltin trichloride, tin 2-ethylhexanoate, and the like.

Examples of the titanium-based compound include dibutyl titanium dichloride, tetrabutyl titanate, and titanium butoxide trichloride.

Examples of the zirconium-based compound include zirconium naphthenate and zirconium acetylacetonate.

Examples of the lead-based compound include lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate.

Examples of the cobalt-based compound include cobalt 2-ethylhexanoate and cobalt benzoate.

Examples of the zinc-based compound include zinc naphthenate and zinc 2-ethylhexanoate.

Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo-(5,4,0)-undecene-7 and the like.

The catalyst (C) may be used alone or in combination of two or more. The amount of the catalyst (C) to be used is preferably 0.01 parts by weight or more, more preferably 0.08 parts by weight or more, still more preferably 0.1 parts by weight or more, and particularly preferably 0.15 parts by weight, based on 100 parts by weight of the polyol (A). the above. The upper limit of the amount of use of the catalyst (C) is preferably 5 parts by weight or less. When the amount of the catalyst (C) to be used is adjusted to the above range, the adhesive of the present invention is excellent in initial reworkability when attached to the adherend, and is excellent in reliability after passage of time. Again, by the amount of catalyst (C) Adjusted to the above range, the adhesive of the present invention can simultaneously achieve excellent wettability, low contamination, and reduced stickiness. Further, in particular, a polyol having two OH groups having a number average molecular weight Mn of less than 6,000 and a polyol having three or more OH groups having a number average molecular weight Mn of less than 2,000 are used in combination as the polyol (A). In the case where the amount of the catalyst (C) used is adjusted to the above range, the adhesive of the present invention is excellent in initial reworkability when attached to the adherend, and is excellent in reliability after passage of time. . Further, in particular, a polyol having two OH groups having a number average molecular weight Mn of less than 6,000 and a polyol having three or more OH groups having a number average molecular weight Mn of less than 2,000 are used in combination as the polyol (A). At the time of adjusting the amount of the catalyst (C) to the above range, the adhesive of the present invention can simultaneously achieve excellent wettability, low contamination, and reduced stickiness.

The adhesive of the present invention may contain any appropriate other components in addition to the above-described polyurethane-based resin, within the range not impairing the effects of the present invention. Examples of such other components include other resin components other than the polyurethane resin, a thickener, an inorganic filler, an organic filler, a metal powder, a pigment, a foil, a softener, and a plasticizer. Agent, anti-aging agent, conductive agent, ultraviolet absorber, antioxidant, light stabilizer, surface lubricant, leveling agent, anti-corrosion agent, heat stabilizer, polymerization inhibitor, lubricant, solvent, etc.

The adhesive layer comprising the adhesive of the present invention can be formed by any suitable method. Such an adhesive layer can be obtained by applying an adhesive to a suitable support to form an adhesive. In this case, a member which becomes a base material layer of the surface protective film may be used as a support, and an adhesive obtained by forming on any other suitable support may be finally transferred to a substrate which becomes a surface protective film. On the members of the layer, an adhesive layer is formed.

Examples of the method of applying the material of the adhesive include roll coating, gravure coating, reverse coating, roll coating, spray coating, air knife coating, and a die coater. Extrusion coating, etc.

"B. Adhesive sheet and surface protective film"

The adhesive sheet of the present invention has an adhesive layer containing the adhesive of the present invention on at least one side of the substrate layer. The surface protective film of the present invention has an adhesive layer containing the adhesive of the present invention on one side of the substrate layer. The adhesive sheet of the present invention can be preferably used, for example, for the purpose of adhering and fixing various members such as an optical member or an electronic member to each other. The surface protective film of the present invention can be preferably used, for example, for attachment to a surface of an optical member or an electronic member to protect the surface, and the like.

As the thickness of the adhesive layer, any appropriate thickness can be employed depending on the application. The thickness of the adhesive layer is preferably from 1 μm to 100 μm, more preferably from 3 μm to 50 μm, still more preferably from 5 μm to 30 μm.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing an adhesive sheet or a surface protective film according to a preferred embodiment of the present invention. The adhesive sheet or surface protection film 10 includes a base material layer 1 and an adhesive layer 2. The adhesive sheet or surface protective film of the present invention may further have any other suitable layer (not shown) as needed.

The adhesive sheet of the present invention may also have an adhesive layer comprising the adhesive of the present invention on both sides of the substrate layer. That is, in FIG. 1, an adhesive layer may be further provided on the side of the base material layer 1 opposite to the adhesive layer 2.

In the case where the surface of the base material layer 1 is not provided with the adhesive layer 2, the surface may be formed to form a wound body which is easy to rewind, and for example, a fatty acid guanamine may be added to the base material layer. A release treatment is carried out by using an ethylenimine or a long-chain alkyl-based additive, or a coating layer containing any appropriate release agent such as a polyfluorene-based, long-chain alkyl-based or fluorine-based additive.

The adhesive sheet and the surface protective film of the present invention may be bonded to a release liner having a release property.

The thickness of the adhesive sheet and the surface protective film of the present invention can be set to any appropriate thickness depending on the application. From the viewpoint of sufficiently exhibiting the effects of the present invention, it is preferably 10 μm to 300 μm, more preferably 15 μm to 250 μm, still more preferably 20 μm to 200 μm, still more preferably 25 μm to 150 μm.

The adhesive sheet and the surface protective film of the present invention preferably have high transparency. By the present invention The adhesive sheet and the surface protective film have high transparency, and can be accurately inspected while being attached to the surface of the optical member or the electronic member. The haze of the pressure-sensitive adhesive sheet and the surface protective film of the present invention is preferably 5% or less, more preferably 4% or less, still more preferably 3% or less, still more preferably 2% or less, and most preferably 1% or less.

As the thickness of the base material layer, any appropriate thickness can be employed depending on the application. The thickness of the substrate layer is preferably from 5 μm to 300 μm, more preferably from 10 μm to 250 μm, still more preferably from 15 μm to 200 μm, still more preferably from 20 μm to 150 μm.

The base material layer may be a single layer or a laminate of two or more layers. The substrate layer can also be an extender.

As the material of the substrate layer, any appropriate material can be used depending on the application. For example, plastic, paper, metal film, non-woven fabric, etc. are mentioned. It is preferably plastic. The substrate layer may comprise one material and may also comprise two or more materials. For example, it is also possible to include more than two types of plastics.

Examples of the plastic material include a polyester resin, a polyamide resin, and a polyolefin resin. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of the polyolefin-based resin include a homopolymer of an olefin monomer, a copolymer of an olefin monomer, and the like. Specific examples of the polyolefin-based resin include a homopolypropylene; a propylene-based copolymer such as a block system, a random system, or a graft system in which a vinyl component is used as a copolymerization component; and a reactor directly prepares TPO ( Thermoplastic PolyOlefin, thermoplastic polyolefin); ethylene polymer with low density, high density, linear low density, ultra low density, etc.; ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, A vinyl copolymer such as an ethylene-ethyl acrylate copolymer, an ethylene-butyl acrylate copolymer, an ethylene-methacrylic acid copolymer, or an ethylene-methyl methacrylate copolymer.

The substrate layer may contain any suitable additives as needed. Examples of the additive which may be contained in the substrate layer include an antioxidant, an ultraviolet absorber, a light stabilizer, and an anti-oxidant. Electrostatic agents, fillers, pigments, and the like. The kind, number, and amount of the additives which can be contained in the base material layer can be appropriately set depending on the purpose. In particular, when the material of the base material layer is a plastic, it is preferable to contain several kinds of the above additives for the purpose of preventing deterioration or the like. From the viewpoints of improvement in weather resistance, etc., as an additive, an antioxidant, a UV absorber, a light stabilizer, and a filler are especially preferable.

As the antioxidant, any appropriate antioxidant can be employed. Examples of such an antioxidant include a phenol-based antioxidant, a phosphorus-based processing heat stabilizer, a lactone processing heat stabilizer, a sulfur-based heat-resistant stabilizer, and a phenol-phosphorus-based antioxidant. The content ratio of the antioxidant is preferably 1 part by weight or less, more preferably 0.5 or less, based on 100 parts by weight of the matrix resin of the base material layer (when the base material layer is a blend, the blend is a matrix resin). It is preferably 0.01 parts by weight to 0.2 parts by weight, based on the parts by weight or less.

As the ultraviolet absorber, any appropriate ultraviolet absorber can be used. Examples of such an ultraviolet absorber include a benzotriazole-based ultraviolet absorber and three. It is a UV absorber, a benzophenone type ultraviolet absorber, etc. The content ratio of the ultraviolet absorber is preferably 2 parts by weight or less, more preferably 100 parts by weight or less based on 100 parts by weight of the matrix resin forming the substrate layer (in the case where the base layer is a blend). It is 1 part by weight or less, and more preferably 0.01 part by weight to 0.5 part by weight.

As the light stabilizer, any appropriate light stabilizer can be employed. Examples of such a light stabilizer include a hindered amine light stabilizer and a benzoate light stabilizer. The content ratio of the light stabilizer is preferably 2 parts by weight or less, more preferably 100 parts by weight or less based on 100 parts by weight of the matrix resin forming the base material layer (in the case where the base material layer is a blend). It is 1 part by weight or less, and more preferably 0.01 part by weight to 0.5 part by weight.

As the filler, any appropriate filler can be employed. As such a filler, an inorganic filler etc. are mentioned, for example. Specific examples of the inorganic filler include carbon black, titanium oxide, and zinc oxide. 100 parts by weight with respect to the matrix resin forming the substrate layer (in the case where the substrate layer is a blend, the blend is a matrix resin), and the filler is contained The ratio is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, still more preferably 0.01 parts by weight to 10 parts by weight.

Further, as an additive, for the purpose of imparting antistatic properties, an inorganic, a low molecular weight or a high molecular weight antistatic agent such as a surfactant, an inorganic salt, a polyhydric alcohol, a metal compound or carbon may be preferably used. Particularly, from the viewpoint of contamination and adhesion maintenance, a high molecular weight antistatic agent or carbon is preferred.

The adhesive sheet and surface protective film of the present invention can be used in any suitable application. The adhesive sheet of the present invention can be preferably used, for example, for the purpose of adhering and fixing various members such as an optical member or an electronic member to each other. The surface protective film of the present invention can be preferably used, for example, for attaching to the surface of an optical member or an electronic member to protect the surface or the like.

The optical member to which the adhesive sheet of the present invention is attached can be bonded and peeled off a plurality of times by manual work.

The electronic component to which the adhesive sheet of the present invention is attached can be attached and peeled off a plurality of times by manual work.

The optical member to which the surface protective film of the present invention is attached can be bonded and peeled off a plurality of times by manual work.

The electronic component to which the surface protective film of the present invention is attached can be bonded and peeled off a plurality of times by hand.

The adhesive sheet and the surface protective film of the present invention can be produced by any appropriate method. Such a production method can be carried out, for example, according to any appropriate production method such as the following method: (1) a solution or heat fusion of a material for forming an adhesive layer (for example, a composition containing a polyurethane resin) a method of applying a liquid onto a substrate layer; (2) a method of moving the adhesive layer coated in the form of a separator according to the above method to the substrate layer; (3) forming an adhesive layer The material is extruded onto the substrate layer to form a coating (4) a method of extruding a substrate layer and an adhesive layer in two or more layers; (5) a method of laminating a single layer of an adhesive layer on a substrate layer or a double layer together with a laminate layer a method of laminating an adhesive layer; (6) a method of laminating two or more layers of a substrate layer forming material of an adhesive layer and a film or a laminate layer.

Example

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by the examples. Further, the test and evaluation methods in the examples and the like are as follows. In the case of "parts", unless otherwise indicated, "parts by weight" means "% by weight" unless otherwise specified.

<Measurement of initial adhesion to acrylic sheets>

The adhesive sheet or the surface protective film was cut into a width of 20 mm and a length of 100 mm as a sample for evaluation.

The adhesive layer of the evaluation sample was attached to an acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: ACRYLITE L) in an environment of a temperature of 23 ° C and a humidity of 50% RH. . After aging for 30 minutes in an environment of a temperature of 23 ° C and a humidity of 50% RH, a universal tensile tester (manufactured by Meiya Co., Ltd., product name: TCM-1kNB) was used, and the peeling angle was 180° and stretched. Peeling was performed at a speed of 300 mm/min and the adhesion was measured.

<Measurement of adhesion of acrylic sheets to one day after passing at 70 ° C>

The sample for evaluation was prepared in the same manner as the initial adhesion to the acrylic plate, and the adhesion after storage at 70 ° C for one day was measured in the same manner as the initial adhesion.

<Evaluation of initial reworkability>

The adhesive sheet or the surface protective film is cut into a width of 20 mm and a length of 100 mm as Sample for evaluation. The adhesive layer of the evaluation sample was attached to an acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: ACRYLITE) by using a 2 kg roller to reciprocate once in a temperature of 23 ° C and a humidity of 50% RH.

After aging for 30 minutes in an environment of a temperature of 23 ° C and a humidity of 50% RH, the evaluator held the end portion of the sample for evaluation by hand, and peeled at a peeling angle of 100 to 120° in a direction of a length of 100 mm. Peeling was performed at 100 mm/min to 500 mm/min, and the deformation of the substrate was observed. The evaluation of reworkability was carried out in accordance with the following criteria.

○: peelable without deformation of the substrate.

×: The substrate was deformed.

<Evaluation of reliability after the passage of time>

The adhesive sheet or the surface protective film was cut into a width of 20 mm and a length of 50 mm as a sample for evaluation. The sample for evaluation and the acrylic plate were placed on an acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: ACRYLITE L) having a width of 25 mm and a length of 200 mm in an environment of a temperature of 23 ° C and a humidity of 50% RH. The length direction was aligned, and the adhesive layer of the evaluation sample was attached to the test piece by a 2 kg roller.

After storing at 70 ° C for 1 day, the mixture was allowed to stand in an environment of a temperature of 23 ° C and a humidity of 50% RH for 30 minutes, and then the acrylic plate to which the sample for evaluation was attached was attached to the inside of the curved portion to have a sample for evaluation. The length was fixed to a jig having a width of 190 mm, and the ridge of the adhesion surface between the sample for evaluation and the acrylic plate was observed. The evaluation of the reliability after the passage of time was performed in accordance with the following criteria.

○: There was no bulging on the adhesion surface between the sample for evaluation and the acrylic plate.

×: A ridge was formed on the adhesion surface between the sample for evaluation and the acrylic plate.

<Evaluation of wetness>

The surface protective film was cut into 2.5 cm × 10.0 cm as a test piece. The test piece was bonded to an acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: ACRYLITE L) at a speed of 10 m/min by hand to confirm the presence or absence of air bubbles between the test piece and the acrylic plate. Evaluation department It is carried out according to the following criteria.

○: No bubbles.

△: A small amount of air bubbles are caught, but can be easily removed.

×: A large number of air bubbles are involved, and it is not possible to simply remove the air bubbles.

<Evaluation of transparency>

Using a haze meter HM-150 (manufactured by Murakami Color Technology Research Co., Ltd.), according to JIS-K-7136, by haze (%) = (Td/Tt) × 100 (Td: diffuse transmittance, Tt: Total light transmittance) is calculated. The transparency was evaluated according to the following criteria.

○: The haze is 3% or less.

×: The haze exceeds 3%.

[Example 1]

PREMINOL S4006 (manufactured by Asahi Glass Co., Ltd., Mn=5500) which is a polyol having two OH groups as a polyol (A): 70 parts by weight of SANNIX GP-1500 as a polyol having three OH groups (manufactured by Sanyo Chemical Co., Ltd., Mn = 1500): 18 parts by weight of EDP-1100 (manufactured by ADEKA Co., Ltd., Mn = 1100) as a polyol having four OH groups: 12 parts by weight as a polyfunctional isocyanate Trimethylolpropane/toluene diisocyanate addition trimer of the compound (B) (manufactured by Nippon Polyurethane Co., Ltd., trade name: CORONATE L): 12 parts by weight, catalyst (manufactured by Nippon Chemical Industry Co., Ltd., commodity Name: Ethyl acetonide: 0.05 parts by weight, and ethyl acetate was added as a diluent solvent so that the concentration of the solid content component was 50% by weight, and the mixture was stirred by a disperser to obtain a urethane-based pressure-sensitive adhesive composition. The obtained urethane-based pressure-sensitive adhesive composition was applied to a substrate containing a polyester resin "Lumirror S10" (thickness: 38 μm, manufactured by Toray Industries, Inc.) by a supply roll to a thickness of 10 μm after drying. It was aged at a drying temperature of 130 ° C and a drying time of 30 seconds to be dried.

Then, the surface of the release film covered with the release agent is covered with an adhesive layer. The surface was allowed to stand at a temperature of 50 ° C for 12 hours and then left at room temperature (25 ° C) for 1 hour to obtain a surface protective film (1). Further, the obtained surface protective film (1) can also be used as an adhesive sheet.

The evaluation results are shown in Table 1.

[Example 2]

A surface protective film (2) having an adhesive layer was obtained in the same manner as in Example 1 except that the amount of the polyfunctional isocyanate compound (B) used was 24 parts by weight (NCO group / OH group = 1.0). Further, the obtained surface protective film (2) can also be used as an adhesive sheet.

The evaluation results are shown in Table 1.

[Example 3]

As the polyol (A), PREMINOL S4006 (manufactured by Asahi Glass Co., Ltd., Mn = 5500) as a polyol having two OH groups was used: 70 parts by weight of SANNIX GP-1500 as a polyol having three OH groups. (manufactured by Sanyo Chemical Co., Ltd., Mn = 1500): 30 parts by weight, and the amount of the polyfunctional isocyanate compound (B) used is 30 parts by weight (NCO group / OH group = 1.3), and the amount of catalyst used is 30 parts by weight. A surface protective film (3) having an adhesive layer was obtained in the same manner as in Example 1 except that the amount was 0.1 part by weight. Further, the obtained surface protective film (3) can also be used as an adhesive sheet.

The evaluation results are shown in Table 1.

[Example 4]

As the polyol (A), PREMINOL S4011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000) as a polyol having two OH groups: 75 parts by weight, SANNIX GP-5000 as a polyol having three OH groups (manufactured by Sanyo Chemical Co., Ltd., Mn = 5,000): 25 parts by weight, and the amount of the polyfunctional isocyanate compound (B) used is 13 parts by weight (NCO group / OH group = 2.0), and the amount of catalyst used A surface protective film (4) having an adhesive layer was obtained in the same manner as in Example 1 except that the amount was 0.6 parts by weight. Further, the obtained surface protective film (4) can also be used as an adhesive sheet.

The evaluation results are shown in Table 1.

[Example 5]

As the polyol (A), PREMINOL S4011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000) as a polyol having two OH groups was used: 50 parts by weight of SANNIX GP-5000 as a polyol having three OH groups. (manufactured by Sanyo Chemical Co., Ltd., Mn = 5000): 50 parts by weight, and the amount of the polyfunctional isocyanate compound (B) used is set to 17 parts by weight (NCO group / OH group = 2.0), and the amount of the catalyst used is used. A surface protective film (5) having an adhesive layer was obtained in the same manner as in Example 1 except that the amount was changed to 0.8 parts by weight. Further, the obtained surface protective film (5) can also be used as an adhesive sheet.

The evaluation results are shown in Table 1.

[Example 6]

As the polyol (A), PREMINOL S4011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000) as a polyol having two OH groups: 25 parts by weight, SANNIX GP-5000 as a polyol having three OH groups (manufactured by Sanyo Chemical Co., Ltd., Mn = 5,000): 75 parts by weight, and the amount of the polyfunctional isocyanate compound (B) used is 22 parts by weight (NCO group / OH group = 2.0), and the amount of catalyst used. A surface protective film (6) having an adhesive layer was obtained in the same manner as in Example 1 except that the amount was changed to 1.0 part by weight. Further, the obtained surface protective film (6) can also be used as an adhesive sheet.

The evaluation results are shown in Table 1.

[Comparative Example 1]

A surface protective film (C1) having an adhesive layer was obtained in the same manner as in Example 1 except that the amount of the polyfunctional isocyanate compound (B) used was 30 parts by weight (NCO group / OH group = 1.3). Further, the obtained surface protective film (C1) can also be used as an adhesive sheet.

The evaluation results are shown in Table 1.

[Comparative Example 2]

As the polyol (A), PREMINOL S4011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000) as a polyol having two OH groups is used: 100 parts by weight, and more The operation was carried out in the same manner as in Example 1 except that the amount of the functional isocyanate compound (B) was 4.4 parts by weight (NCO group / OH group = 1.0), and the amount of the catalyst used was changed to 0.39 parts by weight. Surface protective film (C2) of the adhesive layer. Further, the obtained surface protective film (C2) can also be used as an adhesive sheet.

The evaluation results are shown in Table 1.

[Example 7]

The surface protective film (1) obtained in Example 1 was attached to a polarizing plate (manufactured by Nitto Denko Corporation, trade name "TEG1465DUHC") as an optical member, and an optical member to which a surface protective film was attached was obtained.

[Example 8]

The surface protective film (1) obtained in Example 1 was attached to a conductive film (manufactured by Nitto Denko Corporation, trade name "ELECRYSTA V270L-TFMP") as an electronic member, and a surface protective film was attached thereto. Electronic components.

Industrial availability

The adhesive sheet or surface protective film of the present invention can be used for attaching to the surface of an optical member or an electronic member to protect the surface or the like.

1‧‧‧ substrate layer

2‧‧‧Adhesive layer

10‧‧‧Adhesive sheet or surface protective film

Claims (15)

An adhesive comprising a polyurethane resin and having an initial adhesion to A immediately after being attached to an acrylic plate, attached to an acrylic plate and passed at 70 ° C When the adhesion force after 1 day is set to B, the initial adhesion force A is 0.001 N/20 mm to 2.0 N/20 mm, and the adhesion force B after one day at 70 ° C is 2.0 times the initial adhesion force A. the above. The adhesive according to claim 1, wherein the polyurethane resin is obtained by hardening a composition containing a polyol (A) having two or more OH groups and a polyfunctional isocyanate compound (B). A urethane resin. The adhesive according to claim 2, wherein the above polyol (A) is two or more kinds of polyols. The adhesive according to claim 3, wherein at least one of the above two or more kinds of polyols is a polyol having two OH groups, and at least one of them is a polyol having three or more OH groups. The adhesive of claim 4, wherein the number average molecular weight Mn of the polyol having two OH groups is 6000 or more, and the number average molecular weight Mn of the polyol having three or more OH groups is 2,000 or more. The adhesive of claim 4, wherein the number average molecular weight Mn of the polyol having two OH groups is less than 6000, and the number average molecular weight Mn of the polyol having three or more OH groups is less than 2,000, and the above plural The equivalent ratio of the NCO group to the OH group in the alcohol (A) and the above polyfunctional isocyanate compound (B) is less than 1.3 based on the NCO group/OH group. The adhesive according to claim 2, wherein the polyol (A) contains 50% by weight or more of a polyol having 2 OH groups. The adhesive according to claim 1, wherein the adhesive is used in an amount of 100 parts by weight based on 100 parts by weight of the above polyol (A) The amount of the catalyst (C) used to obtain the above-mentioned polyurethane resin by curing is 0.01 parts by weight or more. An adhesive sheet having an adhesive layer containing the adhesive of claim 1 on at least one side of the substrate layer. An optical member to which an adhesive sheet as claimed in claim 9 is attached. An electronic component to which an adhesive sheet as claimed in claim 9 is attached. A surface protective film having an adhesive layer containing the adhesive of claim 1 on one side of a substrate layer. A surface protective film according to claim 12, which is used for surface protection of an optical member or an electronic member. An optical member to which a surface protective film as claimed in claim 13 is attached. An electronic component to which a surface protective film as claimed in claim 13 is attached.